AMD gene therapy: the next successes
A single application of gene therapy inhibits the progression of the wet form of age-related macular degeneration. At the 123rd Annual Meeting of the American Academy of Ophthalmology (AAO 2019), researchers will report on six patients with a wet form of age-related macular degeneration, whose vision is stable for eight months after gene therapy. The researchers hope that gene therapy will free patients from monthly injections into the eye cavity, offering a potential "one-time" treatment. This is not just a convenience – such treatment will help more people to preserve their eyesight.
Age-related macular degeneration (AMD), in particular, the wet form, is the most common cause of vision loss and blindness in developed countries in patients over 50 years of age.
AMD is a degenerative eye disease accompanied by the appearance of newly formed defective blood vessels under the retina in the posterior pole of the eye. Fluid flows through these pathological vessels, which permeates the layer of nerve cells, forming scars and killing the cells that provide vision.
The first revolutionary leap in the treatment of AMD occurred relatively recently – about ten years ago – after the approval of antagonists of endothelial vascular growth factor (anti-VEGF therapy). This treatment suppressed the formation of new defective blood vessels, leading in 90% of cases (according to clinical studies) to stop the progression of the wet form of AMD.
However, in practice, the actual percentage of successful therapy approaches 50. One of the main reasons for the lack of effectiveness of treatment is associated with the need for repeated injections of anti-VEGF every four to eight weeks. The drug is administered in the operating room intravitreally, that is, directly into the eye cavity. Elderly patients often get tired of constant visits to an ophthalmologist and stop treatment. In addition, drugs are expensive – this also provokes refusal of treatment.
An alternative to monthly injections was gene therapy, which provides a long-term effect of anti-VEGF on the retina of the eye.
In short, the essence of gene therapy is the ability of the eye to synthesize its own VEGF antagonists. Technically, it is a single intravitreal injection, similar to the one with which the usual administration of anti-VEGF drugs is carried out. To do this, researchers have developed a new generation vector that can insert into the DNA of eye cells genetic material encoding a protein similar to the widely used anti-VEGF drug aflibercept.
In other words, if earlier it was necessary to take aflibercept from an ampoule with a syringe and inject it into the eye, now the patient's eye independently produces aflibercept.
In animal studies, the effectiveness of gene therapy was demonstrated, not inferior to injections of aflibercept, side effects were manageable.
The phase 1 clinical trial included 12 patients who received a single injection of wet AMD gene therapy. Before the study, patients received an average of 35 injections of anti-VEGF, one patient had as many as 109. After the injection of gene therapy, no patient needed repeated treatment for an average of eight months (range from 7 to 11 months).
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru Based on AAO materials: In-Office Gene Therapy for Wet Age-related Macular Degeneration is Coming.